Instance - Tags filter/facet

the*Purpose:*
This UI implementation of the Tags filter covered by MSEARCH-4

User story statement(s):
As a librarian searching inventory
I want to be able to narrow my search by tags
so that I can quickly find relevant records

Scenarios:

1. Scenario:
   • Given the Inventory-es app
   • When the landing page opens
   • Then the Tags filter displayed in the left pane and it is collapsed
2. Scenario:
   • Given the Tags filter is expanded
   • When the user start typing in the filter
   • Then autocomplete suggests available tags
3. Scenario:
   • Given the user typed the tag name in the filter textbox
   • When the user hits enter
   • Then search results are populated with the instances fulfilling the searched tag
4. Scenario:
   • Given the user searched using keywords textbox
   • When the results are populated
   • Then the tags filter is expanded and shows checkboxes with tags that meet the search criteria followed by the number of instances for each tag. The tags are ordered by number of hits in descending order:
5. Scenario:
   • Given the checkbox in the Tags filter/facet
   • When the user selects the checkbox
   • Then only the results list displays only the records that contain selected tag
6. Scenario:
   • Given the checkbox in the Tags filter/facet
   • When the user selects more than one checkbox
   • Then only the results list displays instances that contain either of selected tags(logical disjunction)

Out of scope:

1. Entering same search in search box and selecting filter
2. Showing only top 5 options with by "More..." link